Speech-driven facial animation using a hierarchical model

A system capable of producing near video-realistic animation of a speaker given only speech inputs is presented. The audio input is a continuous speech signal, requires no phonetic labelling and is speaker-independent. The system requires only a short video training corpus of a subject speaking a list of viseme-targeted words in order to achieve convincing realistic facial synthesis. The system learns the natural mouth and face dynamics of a speaker to allow new facial poses, unseen in the training video, to be synthesised. To achieve this the authors have developed a novel approach which utilises a hierarchical and nonlinear principal components analysis (PCA) model which couples speech and appearance. Animation of different facial areas, defined by the hierarchy, is performed separately and merged in post-processing using an algorithm which combines texture and shape PCA data. It is shown that the model is capable of synthesising videos of a speaker using new audio segments from both previously heard and unheard speakers.